@FuchsiaShock But not actual 'time travel' from our point of view. Time-like-closed-curves are where a particle of matter can exist because it was sent back in time to the moment when it started existing. If these occur naturally, they are very short lived. You can't use them to send a message back to yourself, because as a closed loop they will always be existing at the time and place they existed, and in effect cause themselves.
